Buses are often used in the exchange of digital data among multiple electronic devices. Generally, data can be transmitted along a bus by altering the characteristics of one or more signals carried by the bus according to a protocol that is interpretable by other devices connected to the bus. For example, in some buses, data is transmitted electrically by altering the voltage present on one or more electrical conductors as a function of time according to the defining protocol.
Most bus protocols can be classified into one of two groups: a) single-ended buses and b) differential buses. Single-ended buses incorporate single-ended signaling, in which a single wire carries a varying voltage (with reference to a defined ground) that represents a digital signal. In differential buses, a digital data stream is sent via two complementary signals of varying voltage on two separate electrical conductors.
Single-ended signaling is often a good choice for transmitting signals over short distances, such as between components on a single circuit board, as little physical space on the board may be required to implement the bus. However, differential buses can be useful in transmitting data over longer distances, as differential signaling tends to be more resilient against noise and attenuation than single-ended signaling.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.